Combine onion and sausages in heavy large Dutch oven over medium heat. Sauté until sausages brown and onion is very tender, breaking up sausages with back of spoon, about 15 minutes. Add spinach; stir until all spinach liquid evaporates, about 4 minutes. Mix in flour, stir 1 minute. Add broth, half and half and nutmeg. Simmer until mixture is thick, stirring frequently, about 10 minutes. Season with salt and pepper.
